In a biochemical automatic analyzer as an example of an automatic analyzer, for an analysis of components in a biological specimen (hereinbelow referred to as a specimen) such as blood serum and urine, the specimen and a reagent are reacted, and changes of color tone and turbidity resulting from the reaction are optically measured by a photometric unit such as a spectrophotometer.
To cause the specimen and the reagent to be reacted, dispensation thereof from containers respectively housing the specimen and the reagent to a reaction cuvette needs to be performed. For this reason, the automatic analyzer includes a dispensation device automatically sucking and discharging the specimen or the reagent from the container housing it to the reaction cuvette.
In a sample dispensation device dispensing the specimen from a test tube sealed by a sealing cap (hereinbelow referred to as a vacuum blood collection tube) to the reaction cuvette, a dispensation abnormality may occur due to various reasons. A main reason for the dispensation abnormality is probe clogging generated by suction of the specimen.
When the probe is clogged, a predetermined amount of specimen cannot be dispensed into the reaction cuvette, and a reliable analysis result cannot be obtained.
As means for determining the dispensation abnormality, a large number of techniques of providing a pressure sensor inside a dispensation flow path including the probe and detecting the dispensation abnormality such as the probe clogging based on pressure fluctuation are proposed.
In a technique described in PTL 1, pressure inside a vacuum blood collection tube is monitored through a sealing cap and a piercing probe by a pressure sensor. PTL 1 describes that clogging is determined when a detection value of the pressure sensor is a threshold value or higher, or a threshold value or lower.